The United Nations estimates that the Chinese state has detained more than one million Uighurs, the ethnic Muslim minority in China, in camps. Some, have eventually been released. But notably, Communist Party officials have shown reluctance freeing Uighur intellectuals. And according to the Uyghur Human Rights Project based in the US, hundreds of scholars, historians, artists, writers, poets, musicologists, have disappeared. Activists call what's happened a cultural genocide. Correspondent Mathias Bölinger has this report spanning Germany and Xinjiang, as he tells the story of one missing professor from the city of Kashgar.